Tested and fixed typos in sphere Carreau example

[oguevremont]

In preparation for the next release, examples are being checked and tested. This PR addresses the Carreau shear thinning flow around a sphere example.

Description

A few typos were fixed and changes were made to parameter sections mostly, to reflect recent changes.

Miscellaneous (will be removed when merged)

Checklist (will be removed when merged)

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Code related list:

• [x] Lethe documentation is up to date
• [x] Copyright headers are present and up to date
• [x] The branch is rebased onto master
• [x] Code is indented with indent-all and .prm files (examples and tests) with prm-indent
• [x] Links are added to parent .rst files
• [ ] The example is following the standard format

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• [x] Labels are applied
• [ ] There are at least 2 reviewers (or 1 if small feature) excluding the responsible for the merge
• [ ] If this PR closes an issue or is related to a project, it is linked in the "Projects" or "Development" section
• [ ] If any future works is planed, an issue is opened
• [ ] The PR description is cleaned and ready for merge